The invention relates in general to a gas sampling tube, and more particularly, to a sampling tube with closing caps made of an elastic material.
Sampling tubes are used to obtain a gas sample for subsequent laboratory analysis and are, accordingly, distinguished from tubes known as indicator tubes, which are designed for in situ operations. Thus, with the use of conventional indicator tubes, the result of measurement is known instantly, after the measuring operation, for example, due to a coloration readable on a scale. Sampling tubes, however, require a later analysis. This analysis is made at a properly equipped location, usually in a laboratory. In order to obtain a valid result of measurement, the sampling tubes, opened at the location where the sample was taken, must be closed again for transportation to the laboratory, etc.
A prior art sampling tube, employed for testing air for organic compounds, accommodates an activated carbon filler. Until the actual use, the tube is closed by molten glass-sealed tips. For use, the sampling tube is separated from a magazine string of tubes. The tips are opened, and the necessary sample volume is drawn into the tube by suction. The organic compound content of the air is thus adsorbed on the activated carbon. At the end of the sampling operation, the sampling tube is closed with polyethylene caps and sent to a laboratory for analysis of the content of the tube. The handling of a plurality of loosely packaged sampling tubes upon their removal, i.e., closing, keeping track of the samples, and shipping disadvantageously depends to a too large extent, on the skill of the sampler. The need for a remedy is apparent (Drager Bulletin 315, Sept.-Dec.'79, pp 12-15).